Funny thing this,
Over on PN there is an article from the Sunday Morning Photographer on this subject.
The author notes that decades ago, UV filters were used for two reasons. Firstly to cut down on UV and secondly to protect the front elements, which were very soft, from scratches.
He says that today UV filters shouldn't be used in most cases because the UV coatings on lenses are now excellent and that the front elements are a lot harder than they were years ago. Furthermore, he states that UV filters can create 'ghost' images; he even gives two example prints.
I always figured that UV filters were essential; I'm rethinking that now.